Detection of IgG against Rickettsia typhi: a population-based study in southern Kazakhstan

Uvod. Rickettsia typhi svrstava se u skupinu pjegavih tifusa i uzrokuje endemski tifus. Slučajevi endemskog tifusa i seropozitivnosti na R. typhi zabilježeni su u susjednoj Kini i Rusiji. Međutim, o endemskom tifusu u Kazahstanu se malo zna. Svrha ove studije bila je procijeniti prevalenciju IgG protutijela na R. typhi u populaciji južne regije Kazahstana. Metode. U istraživanje je uključeno ukupno 253 osoba (142 žena, 111 muškaraca) u dobi od 1 do 71 godine. Detekcija serumskih IgG protutijela na R. typhi provedena je imunoenzimskim ELISA testom. Rezultati. Ukupna seropozitivnost na R. typhi iznosila je 34,4%. Najveća seroprevalencija od 91,8% zabilježena je u regiji Turkestan. Najniža seropozitivnost od 6,1% otkrivena je u selu Lepsinsk, regija Almaty. Seroprevalencija se nije značajno razlikovala prema spolu. Seropozitivnost kod odraslih pojedinaca nije bila značajno povezana s dobi, ali pozitivni rezultati nisu otkriveni u dobnoj skupini djece mlađe od 14 godina. Zaključak. Dobiveni rezultati potvrđuju aktivnu cirkulaciju R. typhij u regijama Turkestan i Almaty u Kazahstanu. Podaci ukazuju na hitnu potrebu za daljnjim istraživanjima čiji je cilj procijeniti klinički učinak R. typhi u južnoj regiji Kazahstana.Background. Rickettsia typhi belongs to the typhus group of rickettsiae and causes endemic typhus. Cases of endemic typhus and seropositivity to R. typhi have been reported in the neighbouring China and Russia. However, little is known of the endemic typhus in Kazakhstan. The purpose of this study was to evaluate the prevalence of IgG antibodies to R. typhi in the population of southern region of Kazakhstan. Methods. A total of 253 individuals (142 women, 111 men) aged from 1 to 71 years were recruited into the study. Detection of serum IgG antibodies against R. typhi was performed by enzyme-linked immunosorbent assay (ELISA). Results. The overall R. typhi seropositivity has reached 34.4%. The highest seroprevalence of 91.8% was recorded in the Turkestan Region. The lowest seropositivity of 6.1% was detected in the village Lepsinsk, Almaty Region. The seroprevalence did not differ significantly between genders. Seropositivity in adult individuals was not significantly associated with age, but positive results were not detected in the age group of children under 14 years. Conclusion. The obtained results confirm active circulation of R. typhi in the Turkestan and Almaty Regions of Kazakhstan. The data indicate an urgent need for further studies aimed to evaluate the clinical impact caused by R. typhi in the southern region of Kazakhstan

Two case reports of neuroinvasive West Nile virus infection in the Almaty region, Kazakhstan

Background: West Nile virus (WNV) is a member of the genus Flavivirus, which transmitted to humans mainly by mosquitoes. Recent pilot serosurveillance data from the Almaty region, Kazakhstan, suggest widespread WNV circulation in this area. This report includes two cases of neuroinvasive WNV infection in the same family living in a rural area near Tekeli city, Eskeldinsky district, Almaty region, Kazakhstan. Occurring concurrently and manifesting as WNV infection with febrile illness and symptoms of meningoencephalitis. Methods: The study performed retrospective analysis of clinical histories and achieved serum samples obtained from patients with febrile and meningoencephalitic syndromes of unknown origin in the Almaty region spanning from April 1 to October 31, 2019. All sera samples obtained from patients with clinically suspected cases of acute WNV infection were retrospectively tested for WNV and tick-borne encephalitis virus by commercial immunoassays. Two cases were selected. Cases presentation: We report two cases that occurred in August 2019 in a rural area near Tekeli city. Previously healthy 28- and 19-year-old husband and wife with febrile illness and neurological manifestations were hospitalized with the diagnosis of meningoencephalitis of unknown etiology and treated empirically. Retrospective serological analysis showed the presence of high titers of IgG against WNV on day 9 after onset of symptoms in cases. Conclusions: This is the first report of aseptic meningitis with WNV infection in the background in Kazakhstan. The obtained data suggest circulation of WNV in the Almaty region and emphasize importance of laboratory testing for WNV in suspicious cases occurring in the region

Molecular and seroepidemiological investigation of Сoxiella burnetii and spotted fever group rickettsiae in the southern region of Kazakhstan

Ticks are involved in the circulation of a number of human pathogens, including spotted fever group (SFG) Rickettsia spp. and Coxiella burnetii. Little is known about the occurrence of these microorganisms in the southern region of Kazakhstan. In 2018–2022, a total of 726 ticks were collected from bitten humans, livestock, and vegetation in four oblasts of the southern region of Kazakhstan and subjected to DNA extraction. The overall infection rate of Coxiella spp. and Rickettsia spp. in the ticks was 3.3% (24/726) and 69.9% (300/429), respectively. Phylogenetic analysis of ompA and gltA genes revealed the presence of three pathogenic SFG rickettsiae: Candidatus R. tarasevichiae, R. aeschlimannii and R. raoultii in ticks collected from bitten humans. In addition, Candidatus R. barbariae was detected in six Rhipicephalus turanicus ticks for the first time in Kazakhstan. To determine the seroprevalence of C. burnetii infection, we performed a serological analysis of samples collected from 656 domestic ruminants (cattle, sheep, and goats) in the region. Overall, 23.5% (154/656) of the animals tested were positive for IgG against C. burnetii. Seroprevalence at the herd level was 54% (28/52). Goats (43%; 12/28; odds ratio (OD) = 28.9, p < 0.05) and sheep (31.9%; 137/430; OD = 18.1, p < 0.05) had higher seroprevalence than cattle (2.5%; 5/198). Among the risk factors considered in this study, age (p = 0.003) and the oblast in which the animals were sampled (p = 0.049) were statistically associated with seropostivity for Q fever in sheep, according to the results of multivariate logistic regression analysis. Seroprevalence ranged from 0% to 55.5% in animals in different districts of the southern region of Kazakhstan. Active C. burnetii bacteremia was detected in four of 154 (2.6%) seropositive animals. The data obtained provide strong evidence of the presence of pathogenic rickettsiae and C. burnetii in the southern region of Kazakhstan and emphasize the need to improve epidemiological surveillance in the region